title: Simultaneous separation and analysis of water- and fat-soluble vitamins on multi-modal reversed-phase weak anion exchange material by HPLC-UV.
abstract: Several methods for the separation of vitamins on HPLC columns were already validated in the last 20 years. However, most of the techniques focus on separating either fat- or water-soluble vitamins and only few methods are intended to separate lipophilic and hydrophilic vitamins simultaneously. A mixed-mode reversed-phase weak anion exchange (RP-WAX) stationary phase was developed in our laboratory in order to address such mixture of analytes with different chemical characteristics, which are difficult to separate on standard columns. The high versatility in usage of the RP-WAX chromatographic material allowed a baseline separation of ten vitamins within a single run, seven water-soluble and three fat-soluble, using three different chromatographic modes: some positively charged vitamins are eluted in ion exclusion and ion repulsion modes whereas the negatively charged molecules are eluted in the ion exchange mechanism. The non-charged molecules are eluted in a classical reversed-phase mode, regarding their polarities. The method was validated for the vitamin analysis in tablets, evaluating selectivity, robustness, linearity, accuracy, and precision. The validated method was finally employed for the analysis of the vitamin content of some commercially available supplement tablets.
authors.affiliation: Department of Analytical Chemistry, University of Vienna, Vienna, Austria.
authors.forename: Romain
authors.initials: R
authors.lastname: Dabre
authors.forename: Nazanin
authors.initials: N
authors.lastname: Azad
authors.forename: Achim
authors.initials: A
authors.lastname: Schwämmle
authors.forename: Michael
authors.initials: M
authors.lastname: Lämmerhofer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lindner
mesh_terms: D000327:Adsorption; D000837:Anion Exchange Resins / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D056148:Chromatography, Reverse-Phase / Q000295:instrumentation / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D005223:Fats / Q000032:analysis*; D012995:Solubility; D014815:Vitamins / Q000032:analysis* / Q000302:isolation & purification; D014867:Water / Q000032:analysis*
chemical_list: D000837:Anion Exchange Resins; D005223:Fats; D014815:Vitamins; D014867:Water